It always seems very hot in the engine room of my Seal 28 after the engine (Bukh DV20) has run for some time. In fact, I am wondering if the injector and alternator trouble I had when I first got the boat could be attributed to local overheating of these components. I am thinking about providing a ventilator to encourage air circulation, especially around the forward end of the engine. My plan (at the moment) is to fit a dorade box in one of the after cabin cave lockers. There would be a 'clamshell' type ventilator on the outside of the aftercabin coaming and a duct, of about 3 inch diameter against the aftercabin bulkhead and leading down to the engine room. The clamshell would encourage air extraction from the engine room by venturi effect. Airflow into the engine room would be from the saloon, via ventilators into the bilge space. Anybody else had a go at this? Do you think I need a fan too?

All the best for 2007!

Neil

---

I have never spent any thoughts to that problem, because I never had problems with the temperature in the engine room. Of course, it is warm, but very hot? My Bukh´s water temperature is usually around 70° C, so that the surrounding temperature could not be very much higher and the bukh should not take any damage. I think the injector and the alternator should work without any change. Or are perhaps the bearings damaged?
The idea of installing a ventilation through the aft cabin would cause me some belly pain - what if some poisoned air escapes? And surely there would be more noise.
Is there no possibility to let the fresh air from the port side hose stream out at some point quite close to the hottest parts of the engine where it would be drawn in with the effect of cooling those parts? The engine would receive its air some degrees warmer than before, and perhaps loose 1 or 2 hp, but I would try this before drilling to many holes and spend a lot of money.

Best wishes
Gerold

Gerold

---

Hi there, Gerold, many thanks for your reply. On my Bukh, the injectors get very hot - I suppose, because they communicate directly with the combustion chambers. I have had to recondition the internal mating surfaces of the injectors to stop them leaking fuel. I understand they are no longer available as spares - even if I could afford to buy a new set! The oil sump also gets particularly hot. I did read an article in PBO which stated that from an average marine engine, about 33% of the waste heat generated was taken away by the cooling system, another 33% by the oil and the remainder by direct heat radiation and convection. On the Seal 28, the only ventilation into the engine space is set up by the engine's own air intake. On my boat, the hatch in the bottom of the cockpit did not fit very well, so I was getting some extra cooling there, but I have fitted some extra screws to stop the water getting in this year - which is why I thought some cooling help for the engine would be a good idea!

Cheers! Neil

---

Neil,
I think the percentages of the waste heat could be right, but I don´t understand why I don´t have such problems. Could it be that the leaking injectors cause some uncontrolled burning?
Next week I´ll be at the Düsseldorf Boat Exhibition and usually Bukh is there with a stand. I´ll talk about that problem and will ask them, what a new set of injectors would cost. Spare parts or complete used engines you would find even cheaper - at least in Germany - in the magazine of the www.boots-boerse.de  , Rubrik 510 and 511, if you understand a little bit German. In the printed edition I just saw two injectors (new ones) offered in Wilhelmshaven: thomas.wernicke at ewetel.net
If you need more information (Bukh is quite near, in Bremen) send me an Email.
Gerold

Gerold

---

You could be right about my injectors getting hotter than normal, Gerold. I don't think its excess fuel, though. I fitted new nozzles when I refinished all the mating surfaces. It could be corrosion products building up in the waterways of the cylinder head, though. Perhaps I should try some descaler before the crane comes.

I will be interested to hear what Bukh have to say about injectors for the DV20. I did get a price from a Danish company some years ago.
Have a good day at the show!

Cheers! Neil

---

Neil,
I just read your notice about the exhaust bend (I have to look for a dictionary to understand all the technical terms) and don´t know if you are still interested in the injectors.
They told me that all the Bukhs DV 20 received Bosch injectors so that you could easily get spare parts at any Bosch service. Only during a small period in the early 80ies the engines received Brice injectors (hope I got the name right)which can be replaced by Bosch inj.
The problem of overheating was - of course - unknown to them. Maybe the damaged exhaust bend has got to do with it. If necessary, the engine basements(?) can also be used for a DV 24.

By the way: The Düsseldorf Boat Show was disappointing for those who like well built stable boats. The trend leads to simply built, light spacious living rooms on sea (but the sea must not be too rough, please ...).
So I´m looking forward to the coming season with Bumblebee.
Gerold

Gerold

---

Thank you for that info. about the DV20 injectors, Gerold. It was the UK Bukh agent who told me they were no longer available as a replacement unit and only some service parts were available. I will look out for our local Bosch service centre and see what they say.

It's a shame the show was dissapointing. The boats all seem to be so much bigger as well. The salesmen suggest that a 10 - 12m boat is a beginner's craft. My first boat was 2m long and made of builder's hardboard!

Cheers for now! Neil

---